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Water Quality FAQ’s Does our water contain fluoride?
Yes. Fluoride occurs naturally in almost all surface and ground waters. In this area, the natural concentration is 0.1 milligrams per liter. Following a voter initiative in 1972, the fluoride level was increased to 0.9 milligrams per liter, the optimum for cavity prevention. Extensive research over the past 50 years has shown that individuals who drink fluoridated water have fewer dental caries and adding fluoride to drinking water is one of the most cost-effective ways of inhibiting tooth decay. How hard is our water? Our water is on the soft side. Water hardness (a measure of calcium and magnesium concentrations in the water) is the result of a natural accumulation of salts from contact with soil and geological formations. When referring to household use, the term hardness is applied to the soap-neutralizing power of the water and is commonly expressed in grains per gallon. Generally, water with less than 4 grains per gallon hardness is soft, water with 4 to 7 grains per gallon is moderate, and water with greater than 7 grains per gallon is hard. The water that comes from MMWD's reservoirs ranges in hardness from 3 to 5 grains per gallon, while the water that is imported from the Russian River ranges in hardness from 5 to 7 grains per gallon. MMWD blends the Russian River water with reservoir water, so the average hardness of the water served to customers in the northern and central portions of our service area is 4 to 6 grains per gallon. The water hardness for customers in the southern Marin is 3 grains per gallon. How can I be certain there is no lead in my drinking water? You can be sure that the water MMWD provides is free of lead. Annual water quality tests conducted on water samples drawn from the reservoirs and throughout the distribution system consistently have found no detectable amounts of lead in our drinking water. And there's more good news. In response to a federal law passed in 1992 that requires water suppliers to test water drawn at consumers' taps for the presence of lead and copper, which also can pose a significant health risk, MMWD measured lead and copper concentrations in water from the homes of 100 customers. The 100 homes used were chosen because of their high potential to leach lead and copper from household plumbing, representing a "worst case" scenario, based on when they were constructed. The tests found that the presence of both lead and copper was approximately one fourth the standard set by the USEPA. MMWD attributes the favorable results to the naturally high quality of the source water and to MMWD's corrosion control program, begun in 1966. The corrosion control program protects the quality of the drinking water by preventing copper and lead leaching from district pipes. There are additional measures you can take at home to keep lead levels low. First, do not cook with water from the hot water tap, because hot water can dissolve more lead from household plumbing more quickly than cold water. If you need hot water, draw water from the cold tap and heat it on the stove or in a microwave oven. Second, make sure your electrical system is not grounded to one of your water pipes, which can cause corrosion inside the pipe. Check with a licensed electrician or your local building inspector to determine if your wiring can be grounded elsewhere. Do not attempt to change the wiring yourself, because improper grounding can cause electrical shock and fire hazards. Do we have MTBEin our water? No. MMWD's water has no MTBE (methyl tertiary butyl ether), a compound added to gasoline since 1996 to reduce air pollution. Because MTBE is highly water soluble and resists biodegradation, it has more potential to cause water pollution than other gasoline additives. We have tested all MMWD water sources for MTBE and have not detected any. However, we will continue to monitor for it regularly. Sonoma County Water Agency also has tested Russian River water for MTBE and found none. MTBE contaminates waterways above and below the ground from leaking fuel storage tanks, exhaust from motorized watercraft, spillage from marina fueling facilities, and urban storm water runoff. Thanks to the protections we have for our watershed, none of these sources is a factor for MMWD. There are identified sites in Marin that are contaminated with MTBE. Most of these are gas stations, which have underground fuel storage tanks. While MTBE contamination in Marin should be a concern to local residents who want to protect the quality of water that eventually flows into San Francisco Bay, it is not a concern in terms of public drinking water safety. What are disinfection byproducts? Disinfection byproducts are compounds that form when chlorine, a disinfectant, mixes with naturally occurring organic material in the water. Disinfectants are added to water to eliminate water-borne diseases like cholera, dysentery and typhoid. The disinfection byproducts that occur most frequently are trihalomethanes (THMs). Since 1995, when MMWD changed the distribution system disinfectant from chlorine to chloramine (a combination of chlorine and ammonia) MMWD has achieved a 57-percent reduction in THMs on average. The federal standard for THMs is 80 ug/L (Micrograms per liter, or parts per billion), while the THM count in MMWD's water averages 32 ug/L. Should I be worried about cryptosporidium? Cryptosporidium is a microscopic water-borne pathogen that, if ingested by someone with a severely weakened immune system, such as someone with HIV or AIDS, can cause a life-threatening illness. Because of the potential seriousness of infection among immuno-compromised individuals, MMWD has been testing since 1994 for the presence of Cryptosporidium even though there are no federal standards yet. MMWD has found no evidence of Cryptosporidium in the water we deliver to our customers. Why is my water cloudysometimes during the winter? The cloudiness in the water is simply air bubbles being released. Sometimes the water imported from the Russian River in the winter is "supersaturated" with air. This is because the water is drawn from 60 to 80 feet below the river bed and, at these depths, the high winter water levels in the river increase the pressure. The higher pressure, combined with the low winter temperatures, enables water to hold more air. On its way to your tap the water usually warms. When it comes out of your tap, pressure is released, causing the formation of many small air bubbles. There is no health impact of the air bubbles, but if you find the cloudiness unappealing, let the water sit for a few minutes or keep a container of water stored in the refrigerator. Can a home water treatment device make my water even cleaner? The best reason to install a point-of-use water treatment system is to enhance the taste of your tap water. Most devices don't make water more healthful. In fact, if you do not follow carefully the manufacturer's maintenance schedule, you may actually increase the risk of introducing contaminants into your drinking water. Is bottled water better than tap water? It is strictly a matter of taste preference. There is no significant health difference between tap water and bottled water, which comes from many sources, including wells, springs and even the tap. There is a significant cost difference, however. Drinking one liter of MMWD tap water per day costs just $0.29 per year, while drinking one liter of bottled water daily averages $295 per year.
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